Active energy ray-curable composition

ABSTRACT

An active energy ray-curable composition substantially comprising at least one of (meth)acrylates and oligomers thereof represented by the following general formula (I) ##STR1## wherein R represents a hydrogen atom or a methyl group, X represents an alkylene group in which at least one hydrogen atom may be replaced by a hydroxyl group, m is 0 or an integer of 1 to 4, Y represents a hydrocarbon group having a cyclic hydrocarbon moiety therein, and n is 1 or 2. The composition is useful as an adhesive, particularly as one in the production of optical discs.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a composition curable by active energy rayssuch as ultraviolet light, electron beams or radioactive rays, andparticularly to a composition which is suitably used as an adhesive inthe production of optical discs.

2. Description of the Prior Art

Photocurable compositions are known. For example, Japanese Laid-OpenPatent Publication No. 51035/1973 discloses an ultraviolet light-curablecomposition comprising (a) at least one oligo ester which is selectedfrom the group consisting of polyester acrylate, polyester methacrylate,epoxy acrylate and epoxy methacrylate having a boiling point atatmospheric pressure of at least 200° C. and has an acryloyl groupcontent of 5 to 100 mole % based on the total amount of the acryloyl andmethacryloyl groups, (b) a sensitizer and (c) a thermal polymerizationinhibitor. The patent document describes ##STR2## as the component (a).However, when an ultraviolet light-curable composition obtained by usingthis component is used as an adhesive, it has low tensile shear peelstrength and tensile adhesion strength.

U.S. Pat. No. 4,150,170 describes a method of producing an ultravioletlight-curable pressure-sensitive adhesive using an ultravioletlight-curable pressure-sensitive composition comprising an alpha,betaethylenically unsaturated vinyl polymerizable monomer and a benzoinC₁ -C₁₂ hydrocarbon alkyl ether. For example, Example 1 of this patentdescribes a method in which compositions containing butyl acrylate,vinyl acetate and acrylic acid as the above monomer is used.

Japanese Laid-Open Patent Publication No. 142070/1950 discloses aphotosensitive adhesive consisting predominantly of a mixture of

(A) 100 parts by weight of a polymeric substance containing acryloxy ormethacryloxy groups represented by the following formulae (I) to (III)in the molecule ##STR3## wherein R represents a hydrogen atom or amethyl group, n represents an integer of 2 or 3, m is an integer of 1 to4, and l is an interger of 1 to 30, said polymeric substance beingobtained by the addition-reaction of a polymeric substance having anunsaturated double bond in the molecule with an acrylic compoundcontaining a carboxyl or hydroxyl group in the presence of an alkylhypohalite or an N-haloamide compound, and

(B) at least 50 parts by weight of cyclohexyl methacrylate. This patentdocument describes an example in which methacrylic-modifiedpolybutadiene is used as the polymeric substance containing an acryloxyor methacryloxy group.

In the prior art, optical discs are produced by bonding a recordinglayer provided on a substrate and a light-pervious protecting materialby means of a photocuring agent. A photocurable composition which can beused in this application is desirably required to have excellent tensileshear peel strength and tensile adhesion strength, effect bonding withina short period of time, and be free from components that adverselyaffects the recording layer, and further not to impair the opticalproperties such as transparency of the substrate.

Photocurable compositions known heretofore do not sufficiently satisfyall of these properties.

SUMMARY OF THE INVENTION

It is an object of this invention to provide an adhesive having theaforesaid desirable properties in combination.

Another object of this invention is to provide a novel compositioncurable by irradiation of active energy rays such as ultraviolet light,electron beams or radioactive rays.

The above objects are achieved in accordance with this invention by anactive energy ray-curable composition substantially comprising at leastone of (meth)acrylates and oligomers thereof represented by thefollowing general formula (I) ##STR4## wherein R represents a hydrogenatom or a methyl group, X represents an alkylene group in which at leastone hydrogen atom may be replaced by a hydroxyl group, m is 0 or aninteger of 1 to 4, Y represents a hydrocarbon group having a cyclichydrocarbon moiety therein, and n is 1 or 2.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1 and 2 are views showing the states of test pieces used formeasuring adhesion strengths in this invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention provides an active energy ray-curable compositionsubstantially comprising at least one of (meth)acrylates and oligomersthereof represented by the following general formula (I) ##STR5##wherein R represents a hydrogen atom or a methyl group, X represents analkylene group in which at least one hydrogen atom may be replaced by ahydroxyl group, m is 0 or an integer of 1 to 4, Y represents ahydrocarbon group having a cyclic hydrocarbon moiety therein, and n is 1or 2.

When m is 0 in formula (I), the active energy ray-curable composition ofthis invention has the highest affinity for a substrate and thereforeexcellent adhesion. If m is 5 or more, the composition has poor affinityfor a substrate and therefore inferior adhesion. When n is 3 or more informula (I), the composition has high shrinkage on curing and isexcessively hard so that it rather becomes brittle.

In the (meth)acrylate used in the composition of this invention, theorganic group constituting the portion derived from the alcohol is ahydrocarbon group which without fail has a cyclic hydrocarbon moiety.The hydrocarbon group may be bonded to the (meth)acryloyloxy groupeither directly or through an ether linkage represented by X-O. Xconstituting the ether linkage portion is, in principle, an alkylenegroup of the formula CH_(2l), but at least one of the hydrogen atomsforming the alkylene group may be replaced by a hydroxyl group. Thenumber of carbon atoms of the alkylene group should preferably be assmall as possible. In the present invention, alkylene groups having 1 to3 carbon atoms are most preferably used. If the number of carbon atomsof the alkylene group is 4 or more, the adhesive property of theresulting composition is reduced.

It is important that the hydrocarbon group constituting Y should containa cyclic hydrocarbon group such as an alicyclic hydrocarbon group, anaromatic hydrocarbon group, a fused polycyclic hydrocarbon group, or acrosslinked hydrocarbon group. Of these, the alicyclic hydrocarbongroup, aromatic hydrocarbon group and crosslinked hydrocarbon group arepreferred. Table 1 below shows especially preferred species of such(meth)acrylates.

In the compositions of the present invention, at least one of oligomersobtained by polymerizing the (meth)acrylates with each other may also beused.

    TABLE 1      Chemical formula Nomenclature      ##STR6##      cyclohexyl acrylate      ##STR7##      norbonyl acrylate      ##STR8##      dicyclopentenyl acrylate      ##STR9##      dicyclopentanyl acrylate      ##STR10##      isobornyl acrylate      ##STR11##      cyclohexyl methacrylate      ##STR12##      hexacyclo[6,6,1,1.sup.3,6,1.sup.10,13,0.sup.2,7,0.sup.9,14      ]-heptadecyl-4-acrylate      ##STR13##      12-methylhexacyclo[6,6,1,1.sup.3,6,1.sup.10,13,0.sup.2,7,0.sup.9,14     ]-heptadecyl-4-acrylate      ##STR14##      11-methylhexacyclo[6,6,1,1.sup.3,6,1.sup.10,13,0.sup.2,7,0.sup.9,14     ]-heptadecyl-4-acrylate      ##STR15##      12-ethylhexacyclo[6,6,1,1.sup.3,6,1.sup.10,13,0.sup.2,7,0.sup.9,14     ]-heptadecyl-4-acrylate      ##STR16##      11-ethylhexacyclo[6,6,1,1.sup.3,6,1.sup.10,13,0.sup.2,7,0.sup.9,14     ]-heptadecyl-4-acrylate      ##STR17##      octacyclo[8,8,1.sup.2,9,1.sup.4,7,1.sup.11,18,1.sup.13,16,0,0.sup.3,8,0.     sup.12,17 ]-docosyl-5-acrylate      ##STR18##      15-methyloctacyclo[8,8,1.sup.2,9,1.sup.4,7,1.sup.11,18,1.sup.13,16,0,0.s     up.3,8,0.sup.12,17 ]docosyl-5-acrylate      ##STR19##      2,7-dimethyltetracyclo[4,4,0,1.sup.2,5,1.sup.7,10 ]dodecyl-3-acrylate      ##STR20##      2,10-dimethyltetracyclo[4,4,0,1.sup.2,5,1.sup.7,10 ]dodecyl-3-acrylate      ##STR21##      11,12-dimethyltetracyclo[4,4,0,1.sup.2,5,1.sup.7,10 ]dodecyl-3-acrylate      ##STR22##      tetracyclo[4,4,0,1.sup.2,5,1.sup.7,10 ]dodecyl-3-acrylate      ##STR23##      9-substituted tetracyclo[4,4,0,1.sup.2,5,1.sup.7,10      ] -dodecyl-3-acrylateR =      methyl, ethyl, propyl, isobutyl, hexyl,cyclohexyl, stearyl, bromo,     fluoro      ##STR24##      8-substituted tetracyclo[4,4,0,1.sup.2,5,1.sup.7,10                     R      ]-dodecyl-3-acrylate =      methyl, ethyl, propyl, isobutyl, hexyl,cyclohexyl, stearyl, bromo,     fluoro      ##STR25##      8,9-disubstituted tetracyclo[4,4,0,1.sup.2,5,1.sup.7,10      ]-dodecyl-3-acrylateR =      methyl, ethyl, propyl, isobutyl, hexyl,cyclohexyl, stearyl, bromo,     fluoro      ##STR26##      hexacyclo[6,6,1,1.sup.3,6,1.sup.10,13,0.sup.2,7,0.sup.9,14      ]heptadecyl-4-methacrylate      ##STR27##      12-methylhexacyclo[6,6,1,1.sup.3,6,1.sup.10,13,0.sup.2,7,0.sup.9,14     ]-heptadecyl-4-methacrylate      ##STR28##      11-methylhexacyclo[6,6,1,1.sup.3,6,1.sup.10,13,0.sup.2,7,0.sup.9,14     ]-heptadecyl-4-methacrylate      ##STR29##      12-ethylhexacyclo[6,6,1,1.sup.3,6,1.sup.10,13,0.sup.2,7,0.sup.9,14     ]-heptadecyl-4-methacrylate      ##STR30##      11-ethylhexacyclo[6,6,1,1.sup.3,6,1.sup.10,13,0.sup.2,7,0.sup.9,14     ]-heptadecyl-4-methacrylate      ##STR31##      octacyclo[8,8,1.sup.2,9,1.sup.4,7,1.sup.11,18,1.sup.13,16,0,0.sup.3,8,0.     sup.12,17 ]-docosyl-5-methacrylate      ##STR32##      15-methyloctacyclo[8,8,1.sup.2,9,1.sup.4,7,1.sup.11,18,1.sup.13,16,0,0.s     up.3,8,0.sup.12,17 ]docosyl-5-methacrylate      ##STR33##      2,7-dimethyltetracyclo[4,4,0,1.sup.2,5,1.sup.7,10      ]dodecyl-3-methacrylate      ##STR34##      2,10-dimethyltetracyclo[4,4,0,1.sup.2,5,1.sup.7,10      ]dodecyl-3-methacrylate      ##STR35##       11,12-dimethyltetracyclo[4,4,0,1.sup.2,5,1.sup.7,10      ]dodecyl-3-methacrylate      ##STR36##      tetracyclo[4,4,0,1.sup.2,5,1.sup.7,10 ]dodecyl-3-methacrylate      ##STR37##      9-substituted tetracyclo[4,4,0,1.sup.2,5,1.sup.7,10      ]-dodecyl-3-methacrylateR =      methyl, ethyl, propyl, isobutyl, hexyl,cyclohexyl, stearyl, bromo,     fluoro      ##STR38##      8-substituted tetracyclo[4,4,0,1.sup.2,5,1.sup.7,10      ]-dodecyl-3-methacrylateR =      methyl, ethyl, propyl, isobutyl, hexyl,cyclohexyl, stearyl, bromo,     fluoro      ##STR39##      8,9-disubstituted tetracyclo[4,4,0,1.sup.2,5,1.sup.7,10      ]-dodecyl-3-methacrylateR =      methyl, ethyl, propyl, isobutyl, hexyl,cyclohexyl, stearyl, bromo,     fluoro      ##STR40##      dicyclopentenyloxyethyl acrylate      ##STR41##      bisoxyethyl bisphenol A diacrylate      ##STR42##      α     phenoxyl-β-hydroxypropyl acrylate

The use of a photopolymerization initiator is not essential in thisinvention. However, when an active energy ray of a relatively lowenergy, for example ultraviolet light, is used, it is desirable toincorporate it in the composition of this invention. Thephotopolymerization initiator may be any of various knownphotopolymerization initiators such as those of the decomposition typewhich upon irradiation of UV or the like decompose and generate radicalsand those of the hydrogen extraction type which generate radicals byhydrogen extraction upon irradiation. Specific examples of thephotopolymerization initiator include benzoin, benzoin ethers such asbenzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether andbenzoin butyl ether, benzophenone compounds such as benzophenone,p-chlorobenzophenone and p-methoxybenzophenone, benzil compounds such asbenzil and benzyl dimethyl ketal, and hydroxyalkylphenyl ketonecompounds such as 1-(4-isopropylphenyl)-2-hydroxy-2-methyl-1-propanone,1-phenyl-2-hydroxy-2-methyl-1-propanone and1-(4-tert-butylphenyl)-2-hydroxy-2-methyl-1-propanone.

The composition of this invention substantially contains the above(meth)acrylate and its oligomer as a main component, and preferablyfurther contains the photopolymerization initiator. Hence, basically, itis of the solventless type.

The (metha)acrylate oligomer used in the composition of this inventionhas an average degree of polymerization of 2 to 100, preferably 2 to 50,and more preferably 2 to 35.

The amount of the (meth)acrylate oligomer used in this invention is 1 to100% by weight, preferably 5 to 95% by weight, more preferably 10 to 90%by weight, based on the total weight of the (meth)acrylate oligomer andthe (meth)acrylate monomer.

The viscosity of the composition of this invention, which depends uponthe average molecular weight and the content in % by weight of the(meth)acrylate oligomer, is, for example, 10 to 50,000 cps, preferably100 to 40,000 cps, more preferably 1,000 to 30,000 cps.

The composition may contain components usually incorporated insolventless adhesives, for example reactive diluents, sensitizers,thickeners, antisagging agents, storage stabilizer and plasticizers.

The amount of the photopolymerization initiator which may be used in thecomposition of this invention is 0.01 to 10 parts by weight, preferably0.05 to 7 parts by weight, more preferably 0.1 to 5 parts by weight, per100 parts by weight of the (meth)acryate and its oligomer.

The composition of this invention is prepared, for example, by thefollowing procedure. At least one monomer of formula (I) and thephotopolymerization initiator are fed into a four-necked flask equippedwith a water-cooled jacket and a stirrer. While the contents were cooledwith water with stirring, ultraviolet light was irradiated from awater-cooled high-pressure mercury lamp with an output of 100 W toeffect photopolymerization in an air atmosphere. The pressure of theinside of the flask was reduced with stirring, and the reaction mixturein purified form is obtained.

The composition of this invention is cured as follows:

The resulting reaction mixture is used to bond adhesion test pieces.Light is irradiated onto the bonded test pieces from a water-cooled highpressure mercury lamp with an output of 3 KW to cure the reactionmixture.

The composition of the present invention is useful, for example, incoating and bonding various substrates, particularly transparentsubstrate materials, above all bonding of optical materials, for examplethe bonding of lenses or optical discs. When the substrate used is onewhich contains a component which is likely to react with a chemicalsubstance and undergo degeneration, for example a recording layer of anoptical disc, it is preferred to use a composition in accordance withthis invention which substantially comprises the above (meth)acrylateoligomer from which monomer components have been removed, and asrequired the photopolymerization initiator.

The composition of this invention exhibit particularly firm adhesivenessto such substrates as those made of polycarbonate polymers,(meth)acrylate polymers, ethylene/cyclic olefin copolymer or olefincopolymers containing 4-methyl-1-pentene as a main component. Oneexamples of the ethylene/cyclic olefin copolymers is a copolymer ofethylene with a monomer component of the following formula (1) whichmonomer assumes the structure of the following formula (2) in thecopolymer. In the formulae, R¹ to R¹² are identical or different andeach represents hydrogen, alkyl or halogen, R⁹ or R¹⁰ and R¹¹ or R¹² mayform a ring together, n is 0 or a positive number of at least 1, when R⁵to R⁸ recur a plurality of times, they may be identical or different.##STR43##

According to this invention, there can be provided a novel active energyray-curable composition which cures within a short period of time byirradiation of ultraviolet light, electron beams, radioactive rays,etc., has high adhesion strength, does not impair the optical propertiesof substrates, and is non-polluting because it is of the solventlesstype.

The following examples illustrate the present invention morespecifically.

The adhesion strengths of the compositions in these examples wereevaluated by the following methods.

(i) Tensile shear peel strength

The surface of a test plate, 20×120×2 mm, cut out from aninjection-molded plate of a resin was lightly wiped with gauzeimpregnated with isopropanol, and then the composition of the inventionwas coated on it so that the area of adhesion became 4 cm². Another testplate was superimposed on it, and the assembly was held by quartz glassand fixed. Then active energy ray was irradiated to cure the adhesivecomposition. The cross-sectional surface of the test piece is shown inFIG. 1. In FIG. 1, a=120 mm, b=2 mm, and c=20 mm.

The resulting test piece assembly was pulled at a rate of 50 mm/min.using a tensile tester (Model 1123 made by Instron Co.), and the tensileforce was measured. The tensile shear peel strength was calculated bydividing the tensile force by the area of adhesion.

(ii) Tensile adhesion strength

A test piece A (30×12.7×3 mm) and a test piece B (25×12×6.3 mm) wereprepared from a resin by injection molding. The surfaces of the testpieces were lightly wiped with gauze impregnated with isopropanol. Thecomposition of the invention was then coated on the test piece A, andspread uniformly on the adhesion surface by using the test piece B (areaof adhesion=0.8 cm²). The test pieces were fixed by holding them byquartz glass so that the test piece A was situated atop. By irradiatingactive energy ray onto the assembly, the test pieces were cured. Theapperance of the test piece assembly after bonding is shown in FIG. 2.In FIG. 2, d=30 mm, e=12.7 mm, f=3 mm, g=25 mm, h=12 mm, and i=6.3 mm.

The test piece assembly was pulled at a speed of 50 mm/min. by using atensile tester (Model 1123 made by Instron Co.), and the tensile forcewas measured. The tensile adhesion strength was calculated by dividingthis tensile force by the area of adhesion.

EXAMPLE 1

A 1-liter four-necked flask equipped with a water-cooled jacket and astirrer was charged with 500 g of tetracyclo[4,4,0,1²,5,1⁷,10]-dodecyl-3-acrylate and 1.5 g of1-(4-isopropylphenyl)-2-hydroxy-2-methyl-1-propanone as aphotopolymerization initiator. While the contents were cooled with waterwith stirring, ultraviolet light was irradiated for 10 minutes onto theflask by a 100 W high-pressure mercury lamp placed at a distance of 10cm from the flask to perform photopolymerization in an air atmosphere.Then, the flask was evacuated to 1 torr by using a vacuum pump withstirring, and the reaction mixture was purified for 3 hours. Theresulting reaction mixture was a transparent viscous liquid having aviscosity of 1250 cps.

Gel permeation chromatography showed that the reaction mixture consistedof about 70% by weight of the unreacted monomer and about 30% by weightof oligomers (dimer to eicosamer).

Adhesion test pieces of TPX® (brand TR-18, a product of MitsuiPetrochemical Industries, Ltd.) were bonded by using the resultingreaction mixture. By irradiating light for 30 minutes from a 3 KWhigh-pressure mercury lamp at a distance of 15 cm, the reaction mixtureapplied to the test pieces was cured. The adhesion strengths of theresulting bonded test sample are shown in Table 2.

EXAMPLE 2

Adhesion test pieces of polycarbonate were bonded by the same method asin Example 1 using the reaction mixture obtained in Example 1. Theresults are shown in Table 2.

EXAMPLE 3

Adhesion test pieces of poly(methyl methacrylate) were bonded by thesame method as in Example 1 using the reaction mixture obtained inExample 1. The results are shown in Table 2.

EXAMPLE 4

Adhesion test pieces of ethylene/tetracyclododecene copolymer (ethylene57 mole %; [η]=0.44 dl/g) were bonded by the same method as in Example 1using the reaction mixture obtained in Example 1. The results are shownin Table 2. The [η] was measured at 135° C. using decalin as a solvent.

EXAMPLE 5

The same reaction as in Example 1 was carried out except that 500 g ofcyclohexyl acrylate was used as the monomer, 1 g of1-phenyl-2-hydroxy-2-methyl-1-propanone was used as thephotopolymerization initiator, and the time of irradiating ultravioletlight was changed to 15 minutes. The reaction mixture obtained was atransparent viscous liquid having a viscosity of 2610 cps.

Gel permeation chromatography showed that the reaction mixture consistedof about 40% by weight of the unreacted monomer and about 60% by weightof oligomers (dimer to hexacosamer).

Adhesion test pieces of ethylene/tetracyclododecene shown in Example 4were bonded by using this reaction mixture by the same method as inExample 1. The results are shown in Table 2.

EXAMPLE 6

Example 5 was repeated except that norbornyl acrylate was used as themonomer. The results are shown in Table 2. The resulting reactionmixture was a transparent viscous liquid having a viscosity of 1860 cps.

EXAMPLES 7-9

Example 5 was repeated except that each of the monomers indicated inTable 3 was used. The results are shown in Table 2. The viscosity andappearance of the reaction mixture obtained in each of the examplesshown in Table 3.

EXAMPLES 10-11

Example 5 was repeated except that each of the adherends shown in Table2 was used. The results of the test are shown in Table 2.

                                      TABLE 2                                     __________________________________________________________________________    Example    1              2       3      4     5                              __________________________________________________________________________    Monomer    tetracyclo[4,4,0,1.sup.2,5 -1.sup.7,10 ]-                                                    same as left                                                                          same as left                                                                         same as left                                                                        cyclohexyl                                dodecyl-3-acrylate                  acrylate                       Photopolymerization                                                                      1-(4-isopropylphenyl)-2-                                                                     same as left                                                                          same as left                                                                         same as left                                                                        1-phenyl-2-                    initiator  hydroxy-2-methyl-1-propanone        hydroxy-2-                                                                    methyl-1-                                                                     propanone                      Adherend   TPX (RT-18)    polycarbonate                                                                         polymethyl                                                                           ethylene/                                                                           same as left                                                     methacrylate                                                                         tetracyclo-                                                                   dodecene                                                                      copolymer                            Tensile shear                                                                            9.7            6.9     7.8    11.2  12.3 -peel strength            (kg/cm.sup.2)                                                                 Tensile adhesion                                                                         10.4           7.3     8.5    12.1  13.5                           strength                                                                      (kg/cm.sup.2)                                                                 __________________________________________________________________________    Example     6     7      8     9      10     11                               __________________________________________________________________________    Monomer     norbornyl                                                                           dicyclo-                                                                             dicyclo-                                                                            isoboronyl                                                                           cyclohexyl                                                                           same as left                                 acrylate                                                                            pentyl pentenyl                                                                            acrylate                                                                             acrylate                                                  acrylate                                                                             acrylate                                             Photopolymerization                                                                       1-phenyl-2-                                                                         same as left                                                                         same as left                                                                        same as left                                                                         same as left                                                                         same as left                     initiator   hydroxy-2-                                                                    methyl-1-                                                                     propanone                                                         Adherend    ethylene/                                                                           same as left                                                                         same as left                                                                        same as left                                                                         TPX(RT-18)/                                                                          TPX(RT-18)/                                  tetracyclo-               PR-PET Polyether                                    dodecene                         sulfone                                      copolymer                                                         Tensile shear                                                                             8.4   6.7    7.8   9.4    6.2    5.0                              peel strength                                                                 (kg/cm.sup.2)                                                                 Tensile adhesion                                                                          7.8   7.9    6.9   8.5    5.3    4.7                              strength                                                                      (kg/cm.sup.2)                                                                 __________________________________________________________________________

                  TABLE 3                                                         ______________________________________                                        Example   7           8           9                                           ______________________________________                                        Monomer   dicyclopentyl                                                                             dicyclopentenyl                                                                           isoboronyl                                            acrylate    acrylate    acrylate                                    Viscosity 2960        2780        2640                                        (cps)                                                                         Appear-   transparent same as left                                                                              same as                                     ance      viscous                 left                                                  liquid                                                              ______________________________________                                    

EXAMPLES 12-14

Example 5 was repeated except that each of the acrylates indicated inTable 4 was used as the monomer. The results are shown in Table 4. Thereaction mixtures obtained in these examples were transparent viscousliquids whose viscosities are shown in Table 4.

EXAMPLE 15

Example 5 was repeated except that 250 g of tetracyclo[4,4,0,1²,5,1⁷,10]dodecyl-3-acrylate and 250 g of dicyclopentenyloxyethyl acrylate wereused as the monomer. The results are shown in Table 4.

The resulting reaction mixture was a transparent viscous liquid whoseviscosity is shown in Table 4.

EXAMPLE 16

A reaction mixture was prepared as in Example 1 except that 400 g oftetracyclo[4,4,0,1²,5,1⁷,10 ]dodecyl-3-acrylate and 100 g of bisoxyethylbisphenol A diacrylate were used as the monomer and the ultravioletlight was irradiated for 30 minutes. The resulting reaction mixture hada viscosity of 26,500 cps.

Using the reaction mixture, the same adhesion test as in Example 5 wascarried out. The results are shown in Table 4.

                                      TABLE 4                                     __________________________________________________________________________    Example                                                                            12    13     14   15            16                                       __________________________________________________________________________    Monomer                                                                            dicyclo-                                                                            bisoxyethyl                                                                          gamma-                                                                             tetracyclo[4,4,0,1.sup.2,5,1.sup.7,10 ]-                                                    tetracyclo[4,4,0,1.sup.2,5,1.sup.7,10                                          ]-                                           pentenyloxy-                                                                        bisphenol A                                                                          phenoxy-                                                                           dodecyl-3-acrylate/dicyclo-                                                                 dodecyl-3-acrylate/bisoxy-                    ethylene                                                                            diacrylate                                                                           beta-                                                                              pentenyloxyethyl acrylate                                                                   ethyl bisphenol A diacrylate                  acrylate     hydroxy-                                                                           (1:1 by weight)                                                                             (4:1 by weight)                                            propyl                                                                        acrylate                                                    Photo-                                                                             1-phenyl-2-                                                                         same as left                                                                         same as                                                                            same as left  1-(4-isopropylphenyl)-2-                 polymer-                                                                           hydroxy-2-   left               hydroxy-2-methyl-1-propanone             ization                                                                            methyl-1-                                                                initiator                                                                          propanone                                                                Adherend                                                                           ethylene/                                                                           same as left                                                                         same as                                                                            same as left  same as left                                  tetracyclo-  left                                                             dodecene                                                                      copolymer                                                                Tensile                                                                            10    8.5    10.5 11            11.5                                     shear                                                                         peel                                                                          strength                                                                      (kg/cm.sup.2)                                                                 Tensile                                                                            11    10     12   12            10.5                                     adhesion                                                                      strength                                                                      (kg/cm.sup.2)                                                                 Viscosity                                                                          2050  2870   2300 2780          26500                                    (cps)                                                                         __________________________________________________________________________

COMPARATIVE EXAMPLES 1-17

Example 5 was repeated except that each of the acrylates indicated inTable 5 was used as the monomer. The results of the adhesion tests andthe viscosities of the resulting reaction mixtures are shown in Table 5.

    TABLE 5       Comparative Example 1 Comparative Example 2 Comparative Example     3        Monomer      ##STR44##      ##STR45##      ##STR46##       Photopolymerization 1-phenyl-2-hydroxy- same as left same as left     initiator 2-methyl-1-propanone Adherend ethylene/tetracyclo- same as     left same as left  dodecene copolymer Tensile 1 0 1 shear peel strength     (kg/cm.sup.2) Tensile 2 0 2 adhesion strength (kg/cm.sup.2) Viscosity     (cps) 3200 2800 2510        Comparative Example 4 Comparative Example 5 Comparative Example     6       Monomer      ##STR47##      ##STR48##      ##STR49##       Photopolymerization 1-phenyl-2-hydroxy- same as left same as left     initiator 2-methyl-1-propanone Adherend ethylene/tetracyclo- same as     left same as left  dodecene copolymer Tensile 0 0 0 shear peel strength     (kg/cm.sup.2) Tensile 0 0 0 adhesion strength (kg/cm.sup.2) Viscosity     (cps) 2870 2950 2070        Comparative Example 7 Comparative Example 8 Comparative Example     9        Monomer      ##STR50##      ##STR51##      ##STR52##       Photopolymer 1-phenyl-2-hydroxy- same as left same as left ization     2-methyl-1-propanone initiator Adherend ethylene/tetracyclo- same as     left same as left  dodecene copolymer Tensile 0 0 0 shear peel strength     (kg/cm.sup.2) Tensile 0 0 0 adhesion strength (kg/cm.sup.2) Viscosity     (cps) 1910 3250 3510        Comparative Example 10 Comparative Example 11 Comparative Example     12    Monomer      ##STR53##      ##STR54##      ##STR55##       Photopolymerization 1-phenyl-2-hydroxy- same as left same as left     initiator 2-methyl-1-propanone Adherend ethylene/tetracyclo- same as     left same as left dodecene copolymer Tensile 0 0 0 shear peel strength     (kg/cm.sup.2) Tensile 0 0 0 adhesion strength (kg/cm.sup.2) Viscosity     (cps) 1020 2100 3180        Comparative Example 13 Comparative Example 14 Comparative Example     15    Monomer      ##STR56##      ##STR57##      ##STR58##       Photopolymerization 1-phenyl-2-hydroxy- same as left same as left     initiator 2-methyl-1-propanone Adherend ethylene/tetracyclo- same as     left same as left  dodecene copolymer Tensile 0 0 0 shear peel strength     (kg/cm.sup.2) Tensile 0 0 0 adhesion strength (kg/cm.sup.2) Viscosity     (cps) 2970 1980 2500        Comparative Example 16 Comparative Example 17       Monomer      ##STR59##      ##STR60##       Photopolymerization 1-phenyl-2-hydroxy- same as left initiator     2-methyl-1-propanone Adherend ethylene/tetracyclo- same as left     dodecene copolymer Tensile 0 0 shear peel strength (kg/cm.sup.2) Tensile     0 0 adhesion strength (kg/cm.sup.2) Viscosity (cps) 2090 3520

What is claimed is:
 1. An active energy ray-curable compositioncomprising tetracyclo[4,4,0,1²,5,1⁷,10 ]dodecyl-3-acrylate, an oligomerthereof, or a mixture thereof.
 2. The composition of claim 1 whichcomprises said mixture.
 3. The composition of claim 2 wherein saidoligomer comprises from 5 to 95% by weight of said mixture.
 4. Thecomposition of claim 1 wherein said oligomer has an average degree ofpolymerization of from 2 to
 50. 5. The composition of claim 1 which hasa viscosity of from 100 to 40,000 centipoise.
 6. The composition ofclaim 1 which further comprises dicyclopentenyloxyethyl acrylate orbisoxyethyl bisphenol A diacrylate.
 7. The composition of claim 1 whichfurther comprises a photopolymerization initiator.
 8. The composition ofclaim 7 wherein said photopolymerization initiator comprises1-(4-isopropylphenyl)-2-hydroxy-2-methyl-1-propanone.